The present invention relates to a convergence apparatus of a color television receiver and in particular to a convergence apparatus in which the abnormality of the screen caused by the saturation of the output of the convergence amplifier is prevented.
In a color television receiver, three primary colors, i.e., red, green and blue are combined on a screen such as a fluorescent screen to produce a color image. In this case, it is important in obtaining a fine picture quality to align three primary colors accurately. Assuming that projection cathode-ray tubes of three primary colors are arranged in the transverse direction in a projection TV receiver, projection angles of projection cathode-ray tubes with respect to respective projection screen differ from each other. Rasters projected onto the screen misconverge color by color. In order to correct this misconvergence, a convergence adjustment coil is disposed in a TV receiver. A sawtooth wave current having a horizontal period modulated by a sawtooth wave signal having a vertical period is supplied to the convergence adjustment coil to effect convergence adjustment. Such a convergence apparatus is described in U.S. Pat. No. 4,318,032.
However, the distortion in the waveform of the correction current and the distortion in raster caused by the voltage saturation in the power supply voltage of a convergence amplifier was not paid attention to at all.